Abstract

Enhancing seismic resilience is a critical priority in contemporary structural engineering, particularly for buildings located in earthquake-prone regions. Flat slab systems are increasingly adopted due to their architectural flexibility and construction efficiency; however, their inherent flexibility can reduce lateral stiffness, thereby compromising seismic performance. Drop panels—localized slab thickenings at column-slab intersections—have shown promise in addressing these deficiencies by enhancing both structural stiffness and energy dissipation capacity. Despite these potential advantages, comprehensive evaluations of their global seismic performance under combined gravity and lateral loads remain limited. This study presents a comparative nonlinear static pushover analysis of two four-story reinforced concrete (RC) building models—with and without drop panels—conducted using Extended Three-Dimensional Analysis of Building Systems (ETABS) Nonlinear v9.7.4. The structural design followed Indonesian National Standard (SNI), specifically SNI 1726:2019 (seismic load requirements), SNI 1727:2020 (minimum live loads), SNI 2847:2019 (concrete structural detailing), and General Building Code Regulation (PUBG) 1983 (dead load guidelines). A triangular lateral load distribution was applied incrementally to evaluate structural responses. The results indicate that the inclusion of drop panels led to a shorter fundamental period (0.7493 s), higher base shear capacity (5,750 kN), and lower maximum roof displacement (340 mm), compared to the model without drop panels (0.8380 s, 5,500 kN, and 380 mm, respectively). Furthermore, the drop panel model maintained story drift ratios below 2%, complying with seismic code limits, and demonstrated improved plastic hinge distribution concentrated within Immediate Occupancy (IO) and life safety (LS) performance levels. Although the ductility ratio was slightly lower, the overall energy dissipation capacity improved due to more uniform hinge development. These findings confirm that drop panels represent a cost-effective and structurally efficient solution to enhance the seismic performance of RC flat slab systems.

Keywords

Flat slab systems, Drop panels, Seismic performance, Pushover analysis, Reinforced concrete structures, ETABS simulation.

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